Morrison



Sept. 5, 1950 D. MORRISON 0 MANUALLY PRESE': TIMER Filed Jan. 2, 19 1s2'Sheets-Sheet 1 Sept. 5,1950 n oRmsoN 2,521,301-

' Y MANUALLY PRESET TIMER Filed Jan'. 2, 1948 2 Sheets-Sheet 2JNI/E/VTOE. ,2) when I Patented Sept. 5, 1950 MANUALLY PRESETv TIMERDavid Morrison, Manitowoc, Wis., assignor to Paragon Electric Company,corporation of Wisconsin Two Rivers, '13.,

Application January 2, 1948', Serial No. 131 I 8 Claims.

I l The present invention relates to motor driven timers which operate aswitch or the like at the end of a period of time determined by amanually operable setting device, and particularly to that type whereina pointer of the setting device and a switch controlling cam are bothmounted on a shaft driven by the motor to terminate a timed period; aclutch in a gear train between such shaft and the motor permitting theshaft to be turned manually in. either direction while the motor remainsstationary. One of the dlmculties encountered in this type of apparatusis to secure a rapid and accurate termination of the timed period, dueto the fact that the same-cam surface comes into play'both to start andto terminate a measured period. Thus a surface on a conventional camthat lifts a switch-actuating member slowly to begin a period alsolowers such member slowly on the.

after be pointed out in the claims; but, for a full understanding of theinvention and of its objects and advantages, reference'may be had to thefollowing detailed description taken in connection with the accompanyingdrawings,

' "wherein:

Figure 1 is a side view of a timer, with the casing removed, embodyingthe present invention in a preferred form; Fig. 2 is a section. on line2-2 of Fig. 1, looking down; Fig. 3is a section on line 3-3 of Fig. 1,looking 'up, and only a part of the gear train being shown; Fig. 4

is an elevational view of the parts appearing in Fig. 3, a portion beinga section on line 44 of Fig. 3; Fig. 5 is a section, on a larger scale,on line 4-4 of'Fig. 3, showing only the cam shaft assembly; Fi .6 is aperspective view of the free end of the spring arm that is actuated bythe cam; Fig. '7 is a bottom plan view of the cam shaft assembly, theswitch to be actuated, and an actuator that is controlled by the 'cam,with the parts in their normal, idle positions; Fig. '8 is a viewsimilar to Fig. 7, showing the cam set to determine the length of aperiod to be timed; and Fig. 9 is a view similar to Figs. '1 and 8,showin the cam in the position which it occupies an instant before itreleases-the switch actuator. 1;

In the drawings there is illustrated a timer of more or lessconventional construction wherein there is a gear train mounted betweentwo parallel plates in and ii; the gear train beginning at one end witha pinion l2 and terminating in a gear wheel l3 fixed to a shaft I! thatextends through and is journalled in both of said plates. Pinion I2 isdriven by motor IS in conventional manner. Also, as best shown in Fig.4, gear wheel i3 meshes with a. pinion Ii coaxial with a gear wheel I]that is positively driven by the motor. Pinion l6 and gear wheel ii aremounted on the same shaft l8, a stationary stub shaft fixed on a bracketIS, the pinion and the gear wheel being loose on the shaft and beingrotatable independently of each other. However, these two gear elementsare frictionally held together so that, when the motor-is running, theyrotate in unison. In the arrangement shown, elements l6 and ii aremounted on a sleeve 2. surrounding and rotatable on the stub shaft; thesleeve having at one end an external flange II that abuts against a head22 on the free end of the stub shaft. The distance between the flange Mand the near end of the pinion I6 is greater than the thickness of gearwheel l1; thereby leaving a space between the gear wheel and the flangethat'is filled by a spring spider 23 which yieldingly presses the wheelagainst the pinion to cause them to act as the two members of a frictionclutch. There is preferably placed between the gear wheel and the piniona washer 24 made of a different metal. It will thus be seen that uponproviding the shaft it with a combined finger piece and pointer 25, tocooperate with the usual dial, not shown, the shaft may [be turnedmanually to set the timer, while the motor remains stationary; the motorthen returning the shaft and pointer to the starting point at the end ofa predetermined period of time, in the usual way.

On shaft I 4, in addition to the gear wheel I3, is a cam 26in the formof a disc; the gear wheel being fixed to the shaft and the cam beingfree to move through a limited angle relatively to the shaft. In thearrangement shown, there is pressed onto the shaft It a sleeve 21 whichvaries in diameter to produce two enlarged annular sections 28 and 29between which is disposed a section 8h; of still greater diameter. Gearwheel i3 is s:

on section 23 so as to be fixed to the sleeve. Cam 2-6, which issomewhat thinner than the axial length of section 29, is loose on thatsection. Pressed onto the sleeve beyond section '29 is a collar 3| thatmay conveniently be a piece of plate in the form of a disc to permit itto be made in the form of a stamping. This collar keeps the cam fromdropping off and it may also be conveniently used to form the drivingconnection between the cam and the shaft; the collar is shown as beingprovided with a finger 3i that projects into a slot 32 in the cam. Slot32 is of greater length angularly of the shaft than the width of finger3!, so that there is a limited lost motion between the cam and theshaft.

The cam is shown as being in the form of a, disc having a V-shaped notchor valley 33 in the periphery; one bounding edge 34 for the notch orvalley being the cam face. As shown, this cam face makes an angle Ofabout 30 with a radius which it intersects at the periphery of the disc.

Cooperating with the cam is a suitable switch actuator. In thearrangement shown, the actuator is a spring arm 35 fixed at one end,remote from the cam, to plate It, and extending in or adjacent to theplane of the cam past and in proximity to the latter. The arm is bent atright angles toward the cam opposite the latter, as indicated at 35; thepart 33 having thereon a lateral projection 31 in position to drop intothe notch in the cam disc when the latter is in the zero or neutralposition. A second bend is made in the spring arm to cause flange 36 tomerge into an end section 33 that extends ahead parallel with the mainbody of the arm.

Mounted on plate I I, near the cam and the free end of arm 35, is aswitch device 39 of any desired type, conveniently one that tendsconstantly to open or close, as the case may be, and which is shiftedinto its other position by arm 35 when the latter is lifted out of thenotch in the cam and rides on the unmutilated portion of the edge of thecam disc. In the arrangement shown, the switch is of the push buttontype, its button 40 being operable by a spring lever 4| disposed betweenthe button and the end of arm 35; the lever tending constantly to standclear of the button and being forced against it only when the actuatingarm is lifted by the cam.

It being of course understood that the circuit for the motor is closedwhen switch 33 is operated in setting the timer, as is customary, andthat this switch is normally open, my improved timer operates asfollows:

With the parts in their normal, idle positions, as in Fig. 7, the fingerpiece or pointer is manipu lated to turn the cam in the direction ofarrow A, through any desired distance. The first result of such movementis to take up the lost motion between the shaft and the cam, if finger 3i does not happen to be positioned in the slot as shown in Fig. 7. Afterthe slack has been taken up, projection 31 on spring arm 35 rides upalong the inclined cam surface 34 until it reaches and rests on thecylindrical portion of the periphery of the cam. The distance throughwhich the cam is turned depends on the time interval to be establishedbetween closing and again opening the switch, because the switch remainsclosed unti1 the cam returns to the starting point.

As soon as the timer i set, the motor starts to turn the cam back, suchreturn movement being indicated by arrows B in Figs. 8 and 9. Fig. 8 maybe said to represent either the farthest point to which the cam wasturned or some intermediate point in its return movement; since theeffective angular movement in either direction is almost 360. In orderto reverse the direction of movement of the cam, shaft l4 must turn backfar enough to carry finger 3 from that end of the slot 32 in which it islocated in Fig. 7 to the opposite end, as shown in Figs. 8 and 9. Thusthe shaft. because of this pin and slot connection, cannot later preventthe cam from iump l ahead a distance determined by the length of slot33, whenever the cam is ready to do so. Consequently, as soon as the campasses the point it has reached in Fig. 9, and projection 31 begins toenter the notch in the cam disc, the spring arm through this projectionexerts a powerful pressure on cam face 34 in the direction to drive itahead; and, the disc being. free fromother restraint, it is driven aheadby a snap action until finger 3M acts as a stop and projection 31 hassettled into notch 33 as in Fig. '7. In other words, the effect on theoperation of the switch is the same, in opening, as though cam face 34were radially or undercut at the moment the lug 31 and the notch orvalley in the cam meet upon the return of the cam.

It will be noted that the lost motion between the cam and its shaft mustbe great enough to insure that the spring arm may snap fully into itsswitch opening position before the connection between the cam and itsshaft can interfere.

While I have illustrated and described with particularity only a singlepreferred form of my invention, I do not desire to be limited to theexact details thus illustrated and described, but intend to cover allforms and arrangements that come within the definitions of my inventionconstituting the appended claims.

I claim:

1. In a manually pre-set timer, a rotatable shaft, an element on theshaft for manually adjusting the same, a cam mounted on the shaft so asto provide between them a lost motion and to cause the cam to travelwith the shaft whenever the shaft is turned far enough in eitherdirection to take up the lost 'motion, a yieldable member supported inposition to bear on the cam with considerable pressure, and said camcontaining a valley into which said'member drops when brought intoregistration therewith, one side of the valley being inclined tocooperate with said member to raise the latter out of the valley whenthe shaft is turned in the setting direction and to drive the cam aheadquickly when the shaft is turned back to the starting point.

2. A timer as set forth in claim 1, wherein the yieldable member is aspring arm anchored at one end and having thereon, remote from such end,a projecting cam-engaging part.

3. In a manually pre-set timer, a rotatable shaft, an element on theshaft for manually adjusting the same, a disc mounted on the shaft so asto provide between them a lost motion and to cause the disc to travelwith the shaft whenever the latter is turned far enough in eitherdirection to take up such lost motion, a yieldable member supported inposition to bear on the edge of the disc with considerable pressure, andthe disc containing in the edge thereof a notch into which said memberdrops when brought into registration therewith, one side of the notchbeing inclined to cooperate with said member to move the latter out ofthe notch when the shaft is turned in one direction and to drive the camahead quickly when the shaft is returned to the starting point.

4. A timer as set forth in claim 3, wherein the inclined edge of thenotch lies at an angle of about 30 to a radius which it meets at the edgof the disc.

5. In a manually pre-set timer, a rotatable shaft, an element on theshaft for turning it manually, a disc loose on the shaft and having apin and slot connection therewith to create a lost motion between themupon turning the shaft, a spring-pressed member mounted in position tobear on the edge of the disc and exert considerable pressure, the dischaving in the edge thereof a. notch into which said member drops when itregisters therewith, one bounding edge of the notch constituting a camto cooperate with said member to raise the latter out of the notch orturn the disc relatively to the shaft depending'on the direction inwhich the shaft turns.

6. In a manually pre-set timer, a rotatable shaft, an element on theshaft forturning it manually, a disc mounted on the shaft so as toprovide a lost motion between them and to cause the disc to travel withthe shaft whenever the latter is turned far enough in eitherdirection totake up the lost motionfa spring arm" anchored at one end and havingthereon a projection remote from that end to bear on the edge of thedisc with considerable pressure, said disc containin in the edge thereofa notch into which said projection drops when brought into registrationtherewith, one side of the notch being inclined to cooperate with saidprojection to lift the latter out of the notch when the shaft is turnedin the setting direction and to drive the disc quickly ahead when theshaft is turned back to the starti point, and a switch device positionedin proximity to the free end of said am for actuation by the latter whensaid projection moves out of the notch. V

7. In a device of the character described, a rotatable shaft, a sleevefixed on the shaft and having near one end a short section of larger acollar fixed on said end section, a pin and slot connection between saiddisc and said collar to create a lost motion between them upon turningthe shaft, a spring-pressed member mounted in position to bear on theedge of the disc and exert considerable pressure, the disc having in theedge thereof a notch into which said member drops when it registerstherewith, one bounding edge of the notch constituting a cam to raisesaid member out of the notch when the disc is turned in one directionand to drive the disc ahead quickly when the disc is turned in the otherdirection until the projection is again brought back to the notch.

8. In combination, a rotatable shaft, an element on the shaft forturning it manually, a. motor, a gear train connecting the motor and theshaft and including a friction clutch, a disc mounted on the shaft so asto provide a lost with considerable pressure, said 'disc containingdiameter than the adjacent end section and being of still largerdiameter inwardly from the aforesaid sections, a disc loose on saidshort section,

in the edge thereof a notch into which said projection drops whenbrought into registration therewith, one side of the notch beinginclined to lift said projection out of the notch when the cam is turnedin one direction and to drive the disc ahead quickly when the disc isturned in the other direction until ,the projection is again broughtback to the notch.

DAVID MORRISON.

REFERENCES, CITED I The following references are of record in the fileof this patent:

UNITED STATES PATENTS Number Name Date 2,028,630 Stark Jan. 21, 19362,481,197 Platt et a1. Nov. 1a, 1947

